The present invention generally relates to tracking control systems, and more particularly to a tracking control system which carries out a tracking control in a reproducing mode of a helical scan type magnetic tape recording and reproducing apparatus by controlling a moving speed of a magnetic tape so that a magnetic head accurately scans over a recorded track on the magnetic tape.
Generally, when playing on one video tape recorder (hereinafter simply referred to as a VTR) a magnetic tape which has been recorded on another VTR to carry out a so-called interchanged play, a scanning locus of a magnetic head of the one VTR may not coincide with a recorded track on the magnetic tape. In addition, in the case of a magnetic tape which has been recorded in a long-time recording mode wherein the recording is carried out with a tape moving speed slower than that of a normal recording mode, recorded tracks have a width considerably narrower than that of recorded tracks on a magnetic tape which has been recorded in the normal recording mode. For these reasons, it is necessary to carry out a tracking control operation so that the magnetic head accurately scans over the recorded track on the magnetic tape.
Various tracking control systems have been proposed for the helical scan type VTR. In one example of the conventional tracking control system, a pair of magnetic heads are mounted on respective support members using bimorph, and the magnetic heads are displaced substantially in the track width direction so that the magnetic heads accurately scan over the recorded tracks on the magnetic tape. In another example of the conventional tracking control system, a pair of magnetic heads are mounted on a single support member, and the single support member undergoes a see-saw movement to displace the magnetic heads substantially in the track width direction so that the magnetic heads accurately scan over the recorded tracks on the magnetic tape. However, according to these conventional tracking control systems, the construction of a head assembly becomes complex, and the manufacturing cost of the head assembly accordingly becomes high. In addition, it is necessary to provide a circuit part for generating a control signal which is used to displace the magnetic heads. Hence, when considering the high cost of these conventional tracking control systems, these systems are not suited for a VTR for home.
On the other hand, an inexpensive tracking control system suited for the VTR for home use has also been proposed. According to this system, the tracking control is carried out by controlling a capstan motor which drives a capstan for moving the magnetic tape, as will be described later on in the specification in conjunction with the drawings. However, this system requires a manual adjustment to be performed by the user. In other words, in a reproducing mode of the VTR, the user makes a manual adjustment while monitoring a reproduced picture so that an optimum picture quality is obtained. As a result, this system is disadvantageous in that it is troublesome to perform the manual adjustment and that it takes time to complete the manual adjustment.